High BMI and Diabetes May Be Increasing Global Cancer Burden

29 November 2017

Obesity and diabetes cause around 800,000 cancers a year, with women being almost twice as likely to suffer as men, new research reveals.

Researchers from the Imperial College in London, the University of Kent and the International Agency for Research on cancer analyzed the increase in the number of cancer cases in 175 countries from 1980 to 2002 for the Lancet study on the basis of the incidence of BMI and diabetes.

For men, obesity and diabetes account for more than 40 percent of liver cancer, while for women they are responsible for one-third of cervical cancers, and nearly as many as breast cancer cases.

The authors say that if global rates of diabetes and overweight continue to rise, the share of cancers attributable to the combined factors will increase by over 30 per cent in women and by 20 per cent in men by 2035.

Among the 12 types of cancer examined, the percentage of cases attributed to diabetes and obesity was as high as one-third, the researchers reported in The Lancet Diabetes & Endocrinology, a leading medical journal.

This 5.6% population attributable fraction (PAF) assumes that diabetes and BMI act at least partly independently on cancer risk; the risk factors individually were responsible for a respective 2.0% and 3.9% of cancers.

It is the first time scientists have quantified the number of cancers worldwide caused by these two factors.

When the researchers looked at 12 site-specific cancers believed to have a causal link with BMI and/or diabetes, the PAFs were larger still, at 15.0% in men and 13.3% in women. Liver cancer was the most common diagnosis among males with diabetes and a high BMI; breast cancer was the most common among females. Colorectal cancer was the second commonest, accounting for 63,200 new cancer cases or 21.4 per cent.

"While obesity has been linked to cancer for some time, the relationship between diabetes and cancer has just been formed recently". Breast cancer accounted for almost 30% of cancers thought to be caused by the conditions.

"These projections are particularly alarming when considering the high and increasing cost of cancer and metabolic diseases".

It is thought diabetes and excess fat disrupt the body's hormones and cause inflammation, both of which can fuel cancer growth.

'You can lower your risk of Type 2 diabetes and cancer by maintaining a healthy weight, eating well, keeping active, not smoking and sticking to the recommended alcohol consumption guidelines'.

Dr Pearson-Stuttard added: "It is vital that co-ordinated polices are implemented to tackle the shared risk factors and complications of chronic diseases such as obesity and diabetes".

"The distinct features of cancer patients are evolving throughout the world".

'With nearly 12 million people in the United Kingdom at risk of type 2 diabetes, it's vital that people are supported to reduce their risk.

This article has been republished from materials provided by Imperial college London.